Idiom: Does a one-legged duck swim in circles?

Idiom Definitions for 'Does a one-legged duck swim in circles?'

(US Southern) This is a response given to an unnecessary question for which the obvious answer is yes. Example: If you were to ask an Olympic archer whether she could put an arrow in an apple at ten yards, she could answer: "Does a one-legged duck swim in circles?"('Do one-legged ducks swim in circles?' is also used.)